From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F16AA50C28B; Wed, 30 Sep 2026 18:11:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791915; cv=none; b=Tn4P+F+Z9dD29xON7Vs2W4ZFztQaLMU2PkBnKn3MHYHNKQoL2FJU//qXhcVA6AyGGOmmXHmsZbYo2ntpmWYguIcIrteixCsNuMGSROb7DHOSO3ZGG10HUlB/XLJRI4SPZWYARA+nRptTfRV8ly142hRUhKFkUscMTCqBM94tIiA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791915; c=relaxed/simple; bh=1x36tL41utrSR77gAcfkHHkXQjKTg2+6C/oYyOjr5Q0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UqM7TlrTzMdChw+cD1wFKL/nNQahSl9H4oMH7wkD+pwiGXKXrjdSVijDQCN7If+5cpBZ0hG5P4eSEGRsXwen6+lMGji3mDxtcbacML5olv35Cx6xDiG2uFEBo8GLJD+EjDSIdS/I0M9D5s+zPFsY33ih/AAy6i95i+KOilnILxI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FKqNpB9l; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FKqNpB9l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E8761F000FF; Wed, 30 Sep 2026 18:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791913; bh=WDOC6NVJKdDZzHdJrSszNVVqYFL5QhdollnhBtbesdM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FKqNpB9limCUAsWB66k0qAxp+70WC7X/vwIqpVBwbIV/4EohTT4RufTVK505DZs8S YECRHXm+F2tbb8tGDJOOfdjPXbrg9h7iFKT4+YqPrZMcCKBLBX1qkIwI4zB/x/plxt ItfGZzjfKYYSx7jFqxfe9T0w63S82YN85DtlPFBs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Frank Li , Logan Gunthorpe , Shivank Garg , Vinod Koul , Sasha Levin Subject: [PATCH 5.15 471/752] dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() Date: Wed, 30 Sep 2026 17:25:41 +0200 Message-ID: <20260930152408.466497310@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shivank Garg [ Upstream commit e873c74132f0c5f1452816cd9bb26208f0bba1e1 ] When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/dmaengine.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 7eb3ec8323ccc..ae4121a26c651 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -493,10 +493,13 @@ static int dma_chan_get(struct dma_chan *chan) */ static void dma_chan_put(struct dma_chan *chan) { + struct module *owner; + /* This channel is not in use, bail out */ if (!chan->client_count) return; + owner = dma_chan_to_owner(chan); chan->client_count--; /* This channel is not in use anymore, free it */ @@ -516,7 +519,7 @@ static void dma_chan_put(struct dma_chan *chan) /* This channel is not in use anymore, drop the device ref */ if (!chan->client_count) dma_device_put(chan->device); - module_put(dma_chan_to_owner(chan)); + module_put(owner); } enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) -- 2.53.0